A system for transmitting motion in a bicycle comprises a chain extending between toothed wheels associated with the crank axle and with the hub of the rear wheel. When there are more than one toothed wheel at least one of the crank axle and the hub of the rear wheel, a gearshift is provided comprising a chain guide element, also known as derailleur that moves the chain between the toothed wheels in order to change the gear ratio.
In the case of an electronically servo-assisted gearshift (electronic gearshift), the movement of the derailleur takes place through an electromechanical actuator, typically comprising an electric motor and an articulated parallelogram system. Control electronics drive the actuator automatically, for example based upon one or more detected variables such as travel speed, crank rotation speed, slope of the travel ground, cyclist's heart rate and similar, and/or based upon commands manually entered by the cyclist through suitable control members, for example levers or push buttons.
In order to change the gear ratio under certain conditions, the need may arise to carry out a multiple gearshifting, under this expression in the present disclosure and in the attached claims a gearshifting from an initial toothed wheel to a destination toothed wheel not immediately adjacent thereto being meant.
It is known that during a multiple gearshifting problems may arise if the derailleur and the chain are moved directly from the initial toothed wheel to the destination toothed wheel, caused i.a. by the particularly oblique configuration taken up by the chain and by the fact that, in passing directly from the initial toothed wheel to the destination toothed wheel, the chain does not correctly engage the intermediate toothed wheel(s), with a consequent reduction in the power transmitted by the transmission system to the rear wheel.